RE: NG product export restrictions "Do you know if there is any law in U.S. which prevents or limits the exporting of NG products?"
Unless it's a country with an embargo against it, not to my knowledge.
To me, that article doesn't bring anything new and I'm not sure what the point the author is trying to make.
Needing a licence to export a given product isn't the same thing as having limits. Having a licence merely means the government wants to know who's exporting and maybe have them meet certain standards.
And from a Canadian perspective, most of what we produce here is exported anyway. Up until now, most of it has been to the USA. Starting 2013, more will begin to be exported to other international markets.
As I understand it, the big thing that prevented NG, Propane and Butane from being exported outside of North America has been a lack of port and shipping infrastructure.